1 Field of the Invention
The present invention relates to a position measuring system.
2 Description of the Related Art
Such a position measuring system is known from DE 43 17 022 C1. The position of a scanning unit with respect to a graduated disk is adjusted by a displacement element of an adjustment device in that the displacement element in the form of a screw acts on a lever of a reduction mechanism and displaces the scanning unit in a geared-down manner. This displacement movement is a pivot movement around a flexible joint of the adjustment device.
In accordance with DE 28 44 066 A1 and DE 40 01 848 C1, the displacement also takes place by a lever which pivots the scanning unit around a flexible joint.
However, linear displacement movements of the scanning unit with respect to the scale graduation are demanded in actual use, such as has been explained in EP 0 158 066 A1, for example. For adjusting four photoelectric barriers, which are arranged spatially offset with respect to each other, of a scanning unit of an angle measuring system, the scanning unit can be displaced in the radial direction via elongated holes. There, the radial displacement is called parallel displacement and takes place by two elongated holes. However, a fine adjustment is not possible with this.